将动态SQL的结果转换为sql-server的变量

Question

在存储过程中执行动态SQL，如下所示：DECLARE @sqlCommand nvarchar(1000)DECLARE @city varchar(75)SET @city = 'London'SET @sqlCommand = 'SELECT COUNT(*) FROM customers WHERE City = @city'EXECUTE sp_executesql @sqlCommand, N'@city nvarchar(75)', @city = @city如何在SP中使用count（*）列值作为返回值？

Answer 1

DECLARE @sqlCommand nvarchar(1000)

DECLARE @city varchar(75)

declare @counts int

SET @city = 'New York'

SET @sqlCommand = 'SELECT @cnt=COUNT(*) FROM customers WHERE City = @city'

EXECUTE sp_executesql @sqlCommand, N'@city nvarchar(75),@cnt int OUTPUT', @city = @city, @cnt=@counts OUTPUT

select @counts as Counts

Answer 2

您可能已经尝试过了，但是您的规格是否可以执行此操作？

DECLARE @city varchar(75)

DECLARE @count INT

SET @city = 'London'

SELECT @count = COUNT(*) FROM customers WHERE City = @city

Answer 3

动态版本

    ALTER PROCEDURE [dbo].[ReseedTableIdentityCol](@p_table varchar(max))-- RETURNS int

    AS

    BEGIN

        -- Declare the return variable here

       DECLARE @sqlCommand nvarchar(1000)

       DECLARE @maxVal INT

       set @sqlCommand = 'SELECT @maxVal = ISNULL(max(ID),0)+1 from '+@p_table

       EXECUTE sp_executesql @sqlCommand, N'@maxVal int OUTPUT',@maxVal=@maxVal OUTPUT

       DBCC CHECKIDENT(@p_table, RESEED, @maxVal)

    END

exec dbo.ReseedTableIdentityCol @p_table='Junk'